__init__(self, features, phones): create/initialize instance variables for features and the list of phones (optional) in the plan. When phones is not provided, use an empty list as its initial value. Create an instance variable

class Phone(object):

   def __init__(self, features, phones=[]):

       self.features = features

       self.phones = phones

Explanation:

In python object-oriented programming, an instance variable of a class object is created in the "__init__()" method. the "self" is a convention name used to represent the instance of an object class. The input values are assigned to the object variable with the self.'argument_name' statement.

When the phone argument is not given, the self.phones variable is initialized as an empty list.